Washing machine unbalance switch circuit

ABSTRACT

A washing machine unbalance switch circuit employs a solenoid coil connected in series with the drive motor and normally shunted by its own contacts which are actuated by a lever arm in response to excessive basket movement as may result from an unbalance load. The lever arm is magnetically latched upon opening of the shunt circuit and energization of the coil to maintain the coil as a series impedance in the motor circuit to stop and prevent operation of the motor. In one embodiment the solenoid coil is connected in series with the entire electrical control circuit of the machine to prevent further operation of the machine without first being attended by an operator. A second embodiment employs the solenoid coil in series with the drive motor but ineffective with respect to the remainder of the control circuit so that a presettable program timer remains operable to complete a preset cycle without first requiring the attention of an operator.

United States Patent Getz [ 1 WASHING MACHINE UNBALANCE SWITCH CIRCUIT Edward H. Getz, Watervliet, Mich.

[73] Assignee: Whirlpool Corporation, Benton Harbor,

Mich.

[22] Filed: Aug.20, 1970 [21] Appl.No.: 65,597

[72] Inventor:

Primary Examiner-William i. Price Atwmeydames -..s iett!etenJ mas-i 9529, Donald 1 Jan. 25, 1972 W. Thomas, Gene A. Heth, Franklin C. Hatter, Anthony Niewyk, Robert L. Judd and Hill, Sherman, Meroni, Gross & Simpson [57] ABSTRACT A washing machine unbalance switch circuit employs a solenoid coil connected in series with the drive motor and normally shunted by its own contacts which are actuated by a lever arm in response to excessive basket movement as may result from an unbalance load. The lever arm is magnetically latched upon opening of the shunt circuit and energization of the coil to maintain the coil as a series impedance in the motor circuit to stop and prevent operation of the motor. in one embodiment the solenoid coil is connected in series with the entire electrical control circuit of the machine to prevent further operation of the machine without first being attended by an operator. A second embodiment employs the solenoid coil in series with the drive motor but ineffective with respect to the remainder of the control circuit so that a presettable program timer remains operable to complete a preset cycle without first requiring the attention of an operator.

/ 4 Claims, 3 Drawing Figures WASHING MACHINE UNBALANCE SWITCH CIRCUIT BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to unbalance responsive switch circuits or kickout circuit, and more particularly to unbalance responsive switch circuits for terminating the extraction cycle of a washing program in response to excessive movement of the spinning fluid extraction basket having an unbalance load.

2. Description of the Prior Art The use of unbalance responsive mechanisms for terminat- SUMMARY OF THE INVENTION The primary object of the invention is to provide a simplified yet effective unbalance responsive circuit for a washing machine. According to the invention, an unbalance responsive circuit for a washing machine includes a solenoid coil, normally shunted by a set of switch contacts, connected in series with the machine drive motor. The impedance of the solenoid coil is of sufficient magnitude with respect to the impedance of the drive motor to prevent operation of the drive motor when the shunt switch contacts are open. The shunt contacts are coupled in mechanical relation to the rotating fluid extraction basket of the washing machine by an actuating lever, such lever being operated upon a predetermined movement of the basket. The actuating lever, and thus the shunt switch contacts are magnetically latched in the operated condition until the drive motor circuit is opened by either manual or electrical advancement of a presettable program time which also has contacts connected in series in the drive motor circuit.

An unbalance responsive circuit constructed in accordance with the present invention offers several advantages over known arrangements including: the elimination of a possible current leakage path by placing the solenoid in series rather than in parallel with the drive motor; the elimination excessive switch contacts in that only one set of switch contacts is required; the mechanism may be manufactured asa two-terminal device thereby rendering it incapable of improper installation; and the wiring harness of the machine control circuit is simplified by the elimination of excessive terminals.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects, features and advantages of the invention, its organization, construction and operation will be best understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a front elevation of a washing machine employing unbalance responsive apparatus-the machine being illustrated partially broken away to show the physical relationship between the unbalance responsive apparatus and the fluid extraction rotatable basket;

FIG. 2 is a schematic diagram of a control circuit of a washing machine illustrating a first embodiment of the invention wherein an unbalance responsive apparatus is electrically connected in series with the entire control circuit; and

FIG. 3 is a schematic diagram of a control circuit similar to that of FIG. 2 illustrating another embodiment of the invention wherein an unbalance responsive apparatus is electrically connected in series with only the drive motor of the control circuit.

7 DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 a washing machine is illustrated, and generally referenced 10, as comprising a cabinet II, a tub 12 mounted within the cabinet 11, a perforate wash and fluid extraction basket 13 mounted within the tub I2, and an agitator 14 mounted within the basket 13.

The tub I2 is mounted on a baseplate 23 and secured thereto by fastening means 24. The baseplate 23 is suspended from the cabinet 11 by means not shown for clarity but which permit limited lateral movement to allow for normal operating excursions of the rotating basket.

A drive motor 17 is also mounted on the baseplate 23 as is a transmission 18. The motor 17 has a pulley I9 and the transmission has a pulley 21 each of which receives an interconnecting drive belt 20 for transmitting power from the motor 17 to the transmission 18. A drive shaft 21 is provided to transmit energy from the transmission 18 to the agitator l4 and for the basket 13. I

A kickout switch mechanism 25 (an unbalance responsive device) is mounted on the interiorof the cabinet 11 and includes a solenoid coil 26, an actuator lever 27 disposed in juxtaposition to the baseplate 23 and pivotally mounted at 28 with respect to the solenoid coil 26, and a switch 29 for operation by the lever 27. As is evident from the drawing, excessive lateral movement of thebaseplate 23, as may be caused by an unbalance spinning load in the basket 13, will pivotally move the lever arm 27 to operate the switch 29.

Referring to FIG. 2, a washing machine control circuit which incorporates one embodiment of an unbalance responsive mechanism according tothe invention is illustrated. The control circuit includes a set of input'terminals L1, L2 and N, the pair of terminals L1, L2 for connection to a commercial electrical supply, a 'VAC,,60 I-Iz. supply for example, and the terminal N being a machine ground terminal.

The control circuit comprises a presettable timer having a timer motor 3 and the drive motor 17, an agitate solenoid 44, a fill valve solenoid 45 and a spin solenoid 46 which are generally in parallel with respect to the terminals L1, L2 and selectively connectable thereacross in a programmed sequence by a plurality of timer contacts 32-41. An unbalance control mechanism, schematically illustrated by the solenoid coil 26 and a set of switch contacts 30 (included in the switch 29 of FIG. I), is generally connected in series with the aforementioned control elements in one side (Ll) of the control circuit.

The control circuit further includes a set of switch contacts 42 which are operated by the access door (not shown) of the machine. The timer includes, in addition to the timer motor 31 and the timer contacts 324], a manually settable control knob 16 which is mechanically linked to the timer motor and to the timer contacts and which is mounted on a control console 15 as illustrated in FIG. I. A water level control switch 43 is provided to prevent operation of the drive motor 17 and the timer motor 31 until the tub 12 has been sufficiently filled.

Washing programs vary with respect to water temperature, speed of agitation, speed of spin and the number of operations within a program for normal, delicate and permanent press washing programs; however, there are generally recurring fill and spin operations in each program. The following description therefore assumes that a spin or extraction portion of a program may be followed by subsequent program operations.

In a typical operation, a housewife, the usual operator, will close the access door and switch contacts 42, select a washing program by selectively rotatably positioning the control knob 16 withrespect to corresponding indicia'on the control console 15, and then depress the knob 16. The timer switch contacts 33'are linked to the knob 16 and are closed by such depression. The selection of a washing program closes the timer contacts 32 and sets a cam arrangement within the timer for subsequent selective operation of the contacts 34-41 wherein the program may include: highor low-speed agita- 35 and 36; agitation or draining governed by the closure of 7 timer contacts 37 and 38; filling controlled via timer contacts 39 and 40', and spinning controlled by way of timer contacts If during a spin portion of a washing program the clothing becomes insufficiently distributed about the basket 13 and bunches to efi'ect anunbalance of the spinning basket, the baseplate 23operates the switch 29 via the actuator lever 27 as previously described. In the circuit of FIG. 2 such action will open the switch contacts 30 and remove the shunt normally efi'ected thereby from across the solenoid coil 26. The impedance of the coil 26, which may be on the order of one hundred times that of the drive motor 17, causes a voltage division in the series circuit so established such that the drive motor 17 receives insufiicient energization. The drive motor 17 therefore stops and is maintained in its stopped condition as long as the solenoid coil 26 is connected in series therewith.

Inasmuch as the timer motor 31 is also in series with the solenoid coil 26, it too is insufficiently energized and stops operation, thereby interrupting the selected program.

The unbalance responsive apparatus 25, as previously discussed, latches magnetically to maintain the machine in a shunt down condition until the housewife attends to redistributing the load by pulling the control knob 16 to open the switch contacts 33 to deenergize the solenoid 26 to release the magnetic latch thereof and to deenergize the remainder of the controlcircuit including the motors l7 and 31. The unbalance responsive apparatus 25 is constructed so as to provide an audible alarm upon energization of its coil 26, such alarm being effective to signal the operator that an unbalance condition exists. Upon redistribution of the load and reclosure of the contacts 33 via the knob 16,,the solenoid 26 is again shunted by the switch contacts 30 and effectively out of the circuit, and the washing program then continues under the control of the timer.

Referring now to FIG. 3, there is illustrated another embodiment of the invention connected in a washing machine control circuit. With the exception of the unbalance responsive apparatus, the control circuit of FIG. 3 is the same as the control circuit of FIG. 2; therefore, only an abbreviated circuit is shown in detail, reference to FIG. 2 being available for the reader if necessary.

lN FIG. 3 the unbalance responsive apparatus is serially connected with only the drive motor 17, more specifically it is connected between the drive motor 17 and one side (L2) of the electrical supply terminals.

In this embodiment the kickout or unbalance responsive mechanism operates in the same manner as above described, but the result is not quite the same in that the timer motor is unaffected by the interposition of the solenoid coil 26 by removal of the shunt thereacross. Accordingly, if an unbalance condition occurs, the timer motor will continue to time the operation of the extraction portion of the program without the operation of the motor 17. If the housewife fails to hear the audible alarm, or for some reason chooses to ignore the alarm, the machine will continue through the remainder of the washing program. In the instances where the unbalance condition occurs during the extraction which is followed in the program by a subsequent filling for agitation or rinsing, the clothing may redistribute and the machine will automatically be reset. The machine may be manually reset, however, as described with respect to the circuit of FIG. 2.

While I have described my invention with reference to specific embodiments, many changes and modifications will become apparent to those skilled in the art without departing from; the spirit and scope of my invention, and it is to be understood that I wish to include within the patent warranted thereon, all such changes and modifications as may be reasonable and properly included within the scope of my contribution to the art.

The embodiments of the invention in which an exclusive property or privilege is.claimed are defined as follows:

1. In an automatic washer operable through a cycle of operation including washing and extracting and having a washing mechanism including a rotatable clothes basket adapted to receive fluids and materials to be washed and a motor for driving said rotatable basket for extracting fluids therefrom, the improvement comprising unbalance responsive means connected in-series circuit with said motor operable in response to a predetermined movement of said basket to stop said motor, said unbalance responsive means comprising a solenoid coil having a normally closed switch connected in parallel therewith, said switch being operated from said closed condition to an open condition, in response to said movement, said coil being operative tohold said switch in said open condition.

2. In an automatic washer operable through washing program including washing and extracting and havinga washing mechanism including a rotatable clothes basket adapted to receive fluids and materials to be washed, and a drive motor for driving said rotatable basket for extracting fluids therefrom, and a control circuit for controlling the operation of the washer including a timer having a timer motor and timer contacts operated by said timer motor in a programmed sequence, the improvement comprising unbalance responsive means connected in a series circuit with said drive motor and with said timer motor and operable in response to a predetermined movement of said basket to stop both said drive motor and said timer motor upon the occurrence of basket unbalance during the washing program, said unbalance responsive means comprising a solenoid coil having a normally closed switch connected in parallel therewith, said switch operated from said closed condition to an open condition in response to said movement and said coil being operative to hold said switch in said open condition.

3. ln an automatic washer operable through a washing program including recurring washing, rinsing and extracting, and having a washing mechanism including a rotatable clothes basket adapted to receive fluids and materials to be washed, and a drive motor for driving said rotatable basket for extracting fluids therefrom, and a control circuit for controlling the operation of the washer and a timer having a timer motor connected in parallel with said motor and timer contacts certain ones of which are connected in a series circuit with said drive motor, said timer contacts operated by said timer motor in a programmed sequence, the improvement comprising unbalance responsive means connected in a series circuit with said drive motor and said certain timer contacts and operable in response to a predetermined movement of said basket to stop said drive motor upon the occurrence of an unbalance condition during fluid extracting while permitting said timer motor to continue operation of thewashing program, said unbalance responsive means including an energized solenoid coil connected in said series circuit and having normally closed switch'contacts connected in parallel therewith to normally prevent energization, said switch contacts being operated from said closed condition to an open condition in response to said movement, said coil being operative to hold said switch in said open condition until said coil is deenergized by the open ing of said certain timer contacts.

4. The automatic washer of claim 3 wherein said control circuit includes a master switch and said solenoid coil is deenergized in response to deenergization of said control circuit by opening said master switch. 

1. In an automatic washer operable through a cycle of operation including washing and extracting and having a washing mechanism including a rotatable clothes basket adapted to receive fluids and materials to be washed and a motor for driving said rotatable basket for extracting fluids therefrom, the improvement comprising unbalance responsive means connected in series circuit with said motor operable in response to a predetermined movement of said basket to stop said motor, said unbalance responsive means comprising a solenoid coil having a normally closed switch connected in parallel therewith, said switch being operated from said closed condition to an open condition, in response to said movement, said coil being operative to hold said switch in said open condition.
 2. In an automatic washer operable through washing program including washing and extracting and having a washing mechanism including a rotatable clothes basket adapted to receive fluids and materials to be washed, and a drive motor for driving said rotatable basket for extracting fluids therefrom, and a control circuit for controlling the operation of the washer including a timer having a timer motor and timer contacts operated by said timer motor in a programmed sequence, the improvement comprising unbalance responsive means connected in a series circuit with said drive motor and with said timer motor and operable in response to a predetermined movement of said basket to stop both said drive motor and said timer motor upon the occurrence of basket unbalance during the washing program, said unbalance responsive means comprising a solenoid coil having a normally closed switch connected in parallel therewith, said switch operated from said closed condition to an open condition in response to said movement and said coil being operative to hold said switch in said open condition.
 3. In an automatic washer operable through a washing program including recurring washing, rinsing and extracting, and having a washing mechanism including a rotatable clothes basket adapted to receive fluids and materials to be washed, and a drive motor for driving said rotatable basket for extracting fluids therefrom, and a control circuit for controlling the operation of the washer and a timer having a timer motor connected in parallel with said motor and timer contacts certain ones of which are connected in a series circuit with said drive motor, said timer contacts operated by said timer motor in a programmed sequence, the improvement comprising unbalance responsive means connected in a series circuit with said drive motor and said certain timer contacts and operable in response to a predetermined movement of said basket to stop said drive motor upon the occurrence of an unbalance condition during fluid extracting while permitting said timer motor to continue operation of the washing program, said unbalance responsive means including an energized solenoid coil connected in said series circuit and having normally closed switch contacts connected in parallel therewith to normally prevent energization, said switch contacts being operated from said closed condition to an open condition in response to said movement, said coil being operative to hold said switch in said open condition until said coil is deenergized by the opening of said certain timer contacts.
 4. The automatic washer of claim 3 wherein said control circuit includes a master switch and said solenoid coil is deenergized in response to deenergization of said control circuit by opening said master switch. 